I'm curious, For thoes of you who know the "science" so to speak. What does the gelatin in Fondant do?
And what does the Glycerine do?

I saw a recipe that had no Gelatin in it at all? So I'm curious.

Good ole Google

Gelatin (2) forms thermally reversible gels with water, and the gel melting temperature (<35°C) is below body temperature, which gives gelatin products unique organoleptic properties and flavour release. The disadvantage of gelatin is that it is derived from animal hide and bone (not from trotters as is a common perception), hence there are problems with regard to kosher and Halal status and vegetarians also have objections to its use. Competitive gelling agents like starch, alginate, pectin, agar, carrageenan etc. are all carbohydrates from vegetable sources, but their gels lack the melt in the mouth, elastic properties of gelatin gels.



Safe sweetener
Glycerine is an alcohol (glycerol) and is used as a preservative in the food industry, as well as a sweetener: it is very sweet, yet it contains no sugar. This makes it an ideal sweetener for patients who cannot take sugar, such as the increasing number of Candida sufferers. Vegetable glycerine is said to be the "only acceptable sweetener" for Candida patients. Here are a couple of healthy recipes.